1. Field of the Invention
This invention relates to a framing structure and more particularly to a framing structure having improved means for joining the frame members.
2. Description of the Prior Art
Framing structures comprising frame members with joints that enable quick and rigid assembly are well known. Such structures are often used to form framing modules of various patterns and configurations for shelves, display racks, etageres and other framework systems. Desirable features of these structures are typically ease of assembly without recourse to special skills or tools, rugged mechanical structure, attractiveness and relatively low cost.
In a common construction of joining right angular members, a horizontal member is often provided with hook-on terminals to be supported by cooperating fittings on vertical members. Examples of structures utilizing such joining techniques are described in U.S. Pat. No. 3,465,895, issued Sept. 9, 1969; U.S. Pat. No. 3,195,735 issued July 20, 1965 and U.S. Pat. No. 1,055,522, issued Mar. 11, 1913. Horizontal cross-members, commonly referred to as stringers, that are designed for detachable mounting to vertical posts are often formed of hollow tubing because it is lightweight, relatively inexpensive and commonly available as an off the shelf item. Tubing having a rectangular cross-section is often used because it provides stiffness against bending moments in a particular plane thereby improving the rigidity of the framing structure.